Possibly stupid question

[Gregorsgirl]

I haven't done any deep dives into scientific papers, but I keep hearing that the vaccines don't make you immune to covid, rather lessen symptoms and likelihood of becoming seriously ill. Why? As far as I can remember this was never common knowledge for older diseases we vaccinate for. I also keep seeing that we need 80% vaccinated for herd immunity, why? If the vaccines don't make you immune how could herd immunity be achieved?

I recall reading that AZ does prevent some people from contracting Covid altogether. Not sure of the position with Pfizer/Moderna. I believe there is also now growing evidence that the vaccines reduce transmission.

Because people don't seem to understand that 'there is no evidence it does X' isn't the same is 'there is evidence that it doesn't do X'

Because something has to actually enter you for the immune system to do its thing and fight it off. The vaccine isn't like an invisible force field that would stop the virus entering your body but the vaccine will hopefully have taught your body how to deal with it.

Okay, so the way a virus (any virus) works is that a little bit enters your body. It starts to multiply, spreading as it does so like mold on bread. The virus levels increase until there's enough in your body to make you ill. Your immune system kicks in, fighting the virus to protect you, and you get better.

For covid, two or three days after entering your body it's multiplied to the point that's there's enough virus in your nose to show up on a PCR test.

A day or two after that, there's enough virus in your system that you blow it out whenever you sneeze, cough, or breathe. That means you can give it to other people.

A couple of days after that, there's enough virus in your body to make you feel rubbish.

And a week or so after that, if you're really unlucky, you get very sick indeed.

The vaccine means that your immune system responds faster to the virus infection. So, instead of your immune system not getting on top of it til you've felt lousy for a few days, it might do so before you get any symptoms at all. Or before there's enough virus in you that you can spread it. Or maybe before you can pick it up on a test.

It doesn't stop you from getting infected, because the immune system can't kick in until the virus is there. But it kicks in faster, stopping the infection in its tracks sooner in the progression of the disease.

It totally depends on the route the vaccine takes. The one im in trial for can destroy the virus. Meaning you won't get very ill. It also means transmission rate is low.

@Motorina

Okay, so the way a virus (any virus) works is that a little bit enters your body. It starts to multiply, spreading as it does so like mold on bread. The virus levels increase until there's enough in your body to make you ill. Your immune system kicks in, fighting the virus to protect you, and you get better.

For covid, two or three days after entering your body it's multiplied to the point that's there's enough virus in your nose to show up on a PCR test.

A day or two after that, there's enough virus in your system that you blow it out whenever you sneeze, cough, or breathe. That means you can give it to other people.

A couple of days after that, there's enough virus in your body to make you feel rubbish.

And a week or so after that, if you're really unlucky, you get very sick indeed.

The vaccine means that your immune system responds faster to the virus infection. So, instead of your immune system not getting on top of it til you've felt lousy for a few days, it might do so before you get any symptoms at all. Or before there's enough virus in you that you can spread it. Or maybe before you can pick it up on a test.

It doesn't stop you from getting infected, because the immune system can't kick in until the virus is there. But it kicks in faster, stopping the infection in its tracks sooner in the progression of the disease.

Brilliant explanation: thank you. I wish this could be shared all over the internet, as a way of explaining it simply to people without detailed knowledge of biology.

The vaccine teaches your body how to fight the virus before you get infected, so that if you do, it can fight it straight away rather than work it out from scratch kore slowly if that happens. Which means you're much less likely to get sick at all, and if you do it's much less likely to be so serious, as it will probably be nipped in the bud. It can never be 100% guarantee, it's like a shield: much better than fighting without one.

And if a whole army have shields, and are fighting an enemy without shields, it massively tips the balance in terms of who will "win" at a societal level: if your infection is less intense, you'll pass less viral load on to others to the R0 comes down.

I hate the "war" analogies so apologies for that.

*so the R0 comes down.

OP it might not be common knowledge among the public that older vaccines work this way too (although I’ve always thought people did understand this), but they do! Common knowledge among doctors like me. The COVID vaccines are actually more effective at preventing illness than most of the other vaccines we get in the UK on an individual level. But nothing is 100 percent. Unless a disease is completely eradicated like smallpox. Then we don’t need the vaccine for it anymore. The herd immunity thing is like the army with shields explained above, basically the tipping point where enough people have enough immunity to COVID that it can’t spread easily to another person even if occasionally one person gets an infection.

I might blow your mind by telling you the contraceptive pill isn’t 100 percent either! We do tell people this but the unlucky person who does get pregnant on it is always utterly gobsmacked by it (I have to say generally they’ve forgotten to take a pill somewhere in reality when we go over it).

@Kyliealwayshadthebestdisco

OP it might not be common knowledge among the public that older vaccines work this way too (although I’ve always thought people did understand this), but they do! Common knowledge among doctors like me. The COVID vaccines are actually more effective at preventing illness than most of the other vaccines we get in the UK on an individual level. But nothing is 100 percent. Unless a disease is completely eradicated like smallpox. Then we don’t need the vaccine for it anymore. The herd immunity thing is like the army with shields explained above, basically the tipping point where enough people have enough immunity to COVID that it can’t spread easily to another person even if occasionally one person gets an infection.

I might blow your mind by telling you the contraceptive pill isn’t 100 percent either! We do tell people this but the unlucky person who does get pregnant on it is always utterly gobsmacked by it (I have to say generally they’ve forgotten to take a pill somewhere in reality when we go over it).

I'm shocked at how many people don't understand how all vaccines to date have worked, even in basic terms. I get that the MRNa ones are new so may need some explaining but am shocked and dismayed about scepticism about the ones that are, in mechanism, exactly what we've been using for decades. 😕

@Motorina

Brilliant explanation. Sums it up perfectly.

I'm not so shocked at how many people don't understand, but I'm really concerned that not understanding seems automatically to lead to disbelief.

It is as though people see their own understanding/knowledge as the total of all human knowledge. Newsflash: there are specialists out there.

Obviously I know that vaccines prime the immune system, that they don't prevent viruses entering your system. Tbh I haven't kept up with it all. Why do people think any kinds of questions=disbelief or skepticism? Im not an anti vaxxer, the only one I was dubious about was the hep b vaccine, the first one made me feel odd for ages, so never got the booster.

I'm perfectly capable of understanding how vaccines work, it was always my understanding though that they made you immune to a high percentage, obviously nothing is 100%. Maybe I have absorbed some kind of misinformation by osmosis.

@Gregorsgirl

Obviously I know that vaccines prime the immune system, that they don't prevent viruses entering your system. Tbh I haven't kept up with it all. Why do people think any kinds of questions=disbelief or skepticism? Im not an anti vaxxer, the only one I was dubious about was the hep b vaccine, the first one made me feel odd for ages, so never got the booster.

I'm perfectly capable of understanding how vaccines work, it was always my understanding though that they made you immune to a high percentage, obviously nothing is 100%. Maybe I have absorbed some kind of misinformation by osmosis.

I don't think the comments about scepticism were aimed at you.

It was a good question to ask - I wish more would ask when they don't know rather than assuming things and then making false claims based on them.

Not knowing incidentally is quite understable - I've read numerous reports in the papers that get it wrong. Journos are such a terrible source for science because they always write with absolute authority but get 80% of it completely wrong.

I agree bookworm, there seems to be so much blathering everywhere, people stating things as if they are facts, that are just not. I'm not stupid despite appearances, but the whole thing was just doing my nut in so for the last few months I have avoided news and any covid talk. I'm quite naturally reclusive so have only ventured out locally.

To my mind I really understand the people desperate to get everyone to take the vaccines, I think it's fear that if they don't, things won't go back to how they were.

We are all in an enormous trial and only time will tell. Meanwhile we should just do what we can to help the situation ie have the vaccine.

It’s like chicken pox. You can be immune because you’ve had it, but still be a carrier without knowing and pass it on.

We’ve been in lock down for months and yet children still get chicken pox. Where from?

Chicken pox virus can re-emerge in a person who had wild chicken pox many years previously to produce the illness shingles; people with shingles can shed enough virus to give other people chicken pox. And for months, shingles is not a brief illness often. I'm convinced I got chickenpox off someone who had shingles.

You can''t catch shingles but people with shingles can give someone chickenpox.

If the immune system responds quickly then the person may never have a detectable infection. most vaccines work at their best by stopping any level of detectable infection.

@BluebellsGreenbells

It’s like chicken pox. You can be immune because you’ve had it, but still be a carrier without knowing and pass it on.

We’ve been in lock down for months and yet children still get chicken pox. Where from?

Chickenpox is much more contagious than covid (the R0 is 10-12, so on average 1 person will infect 10-12 other people). It's also contagious before symptoms and not all children have been 100% at home.

The percentage you need to be vaccinated for herd immunity depends on how contagious the disease is and how effective the vaccine is. For example, measles is incredibly contagious (R0 is about 18), but the vaccine is excellent (2 doses are 97% effective) - yet you still need 90% vaccination to keep it in hand which us why the UK no longer classes as measles free... Covid is less infectious, but the vaccine isn't as effective so that's why they think you need 80% for herd immunity.

The one im in trial for can destroy the virus

Would you mind saying which one is it? @Torvean